Several thermal hot springs sit within an easy drive of Cusco. The Vilcanota and Vilcabamba ranges run across the Andean plate boundary, which means geothermal activity surfaces in a number of places as mineral-rich warm water. The springs are a useful post-trek stop.
Lares, 3 hours northeast of Cusco, is the best-known. Four open-air pools between 36°C and 44°C, mineral content heavy in sulphur and iron. The road in crosses the Sacred Valley, so pair it with Pisac on the way out and Ollantaytambo on the way back for a full day. Aguas Calientes (next to Machu Picchu) also has its own hot-spring complex above the town — a 10-minute uphill walk from the main square.
For a trip into the hot springs Peruways runs guided day tours with Quechua-speaking guides covering the geology (plate boundary, thermal flow, mineral content) and the local culture (the springs have been in continuous use since pre-Inca times).
Soak after Rainbow Mountain or the Inca Trail and the next day is noticeably easier. The science is weak but the empirical evidence is strong.
